POPULATION CORE PROJECT SUMMARY In support of the underlying research objectives of the MADRES Center for Environmental Health Disparities, the Population Core will provide an efficient infrastructure to establish, maintain, and acquire health data from a cohort of pregnant women and their infants. The Population Core is central to the successful completion of the integrated program of research proposed in this application. Population Core activities support both Projects 1 and 2 to maximize coordination, integration and efficiency. This will be accomplished by centralizing all aspects of subject contact, health data collection and cohort maintenance for both projects. The Population Core will facilitate coordinated interactions with the Exposure Core in collecting and managing exposure data. Additionally, the Population Core will provide a centralized contact point for both projects and facilitate access to other facility core resources in other centers such as the NIEHS supported-Southern California Environmental Health Sciences Center. Specifically, the Population Core will enroll a cohort of 750 pregnant women and maintain the study cohort as a data resource; perform health data collection on the entire cohort of women during pregnancy and infants at birth; conduct follow-up data collection on the entire cohort of women and infants after birth; and facilitate the recruitment and data collection efforts for two sub-studies. The integrated coordination provided by the Population Core will reduce the need for repetitive subject contact required to accomplish the aims of both projects, establish a unified system for subject tracking, and facilitate streamlined interactions with study subjects?all of which are required for ensuring a successful approach to understanding the impacts of pre- and postnatal/postpartum environmental and social stress on infant growth and maternal weight gain and retention in an urban, environmentally- and health-disparate population.